属性累加(propReduce)

> npm install @turf/meta

Reduce properties in any GeoJSON object into a single value, similar to how Array.reduce works. However, in this case we lazily run the reduction, so an array of all properties is unnecessary. 接收任意类型的 GeoJSON，遍历它的每个要素的 properties 并累加操作。功能类似 Array.reduce()

参数

参数	类型	描述
geojson	FeatureCollection|Feature	任意 GeoJSON 对象
callback	Function	回调，参数依次是 previousValue、currentProperties、featureIndex
initialValue	(*)	初始值

返回

• * - reduce 产生的值

示例

var features = turf.featureCollection([
  turf.point([26, 37], { foo: "bar" }),
  turf.point([36, 53], { hello: "world" })
]);

turf.propReduce(features, function (previousValue, currentProperties, featureIndex) {
  //=previousValue
  console.log(currentProperties);
  //=featureIndex
  return currentProperties;
});
/*
  { foo: "bar" }
  { hello: "world" }
*/